JP2009168765A - Magnetic sensor element and electronic azimuth meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor element for stably and accurately detecting magnetism with little power consumption. <P>SOLUTION: The magnetic sensor element 1 is constituted by winding thin film coils around a magnetic core material 8. The magnetic core material 8 includes one detecting part 8a, two exciting parts 8b and a magnetic connecting part 8c connecting both ends of the detecting part 8a and exciting parts 8b, and has a shape of a figure of 8 as a whole. The two exciting parts 8b of the magnetic core material 8 are respectively wound with exciting coils 4 serving as the thin film coils, to form exciting parts 5. The detecting part 8a of the magnetic core material 8 is wound with a detecting coil 12 serving as the thin film coil, to form a detecting part 13. The number of turns of the detecting coil 12 and exciting coils 4 can thereby be increased to achieve stable and accurate detection of magnetism and a reduction of power consumption. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a small parallel fluxgate type magnetic sensor element and an electronic compass equipped with the magnetic sensor element.

2. Description of the Related Art Conventionally, an electronic azimuth meter is known that is configured by arranging a plurality of magnetic sensor elements and that can electrically detect a direction. By calculating data obtained from outputs of a plurality of magnetic sensor elements arranged orthogonally, an angle from a direction determined as a reference, that is, an azimuth angle can be calculated.
Since the azimuth obtained from this azimuth can be processed as an analog or digital electrical signal, portable information terminals such as mobile phones and PDAs (Personal Digital Assistants), wristwatches, car navigation devices, aircraft attitude detection devices, visually impaired persons Applications to various electronic devices such as consumer devices and game machines are expected.

In recent years, a position information providing service for portable information terminals using GPS (Global Positioning System) has been started. According to this service, the user can know the current position information from the screen display of the terminal. By combining an electronic compass with this terminal, in addition to the position information, it is possible to know information such as which direction the user is facing and where he is heading when walking.
This service using position information and an electronic compass provides useful information to users and is expected to create new business in many industries in the future.

  On the other hand, the above-described portable information terminal tends to be small and thin, and a small and low profile is required as an electronic device mounted therein. The desired width of the magnetic sensor element is about several mm, and the height is particularly required to be 1.5 mm or less, preferably 1.0 mm or less.

In order to solve such a problem, a parallel fluxgate type magnetic sensor element capable of being miniaturized has been proposed (for example, see Patent Document 1). FIG. 5 is a plan view showing the configuration of the magnetic sensor element 100 described in Patent Document 1. As shown in FIG.
The magnetic sensor element 100 has a configuration in which a thin film coil is wound around a magnetic core material 108. The magnetic core material 108 includes a magnetic sensing part 108a and magnetic collecting parts 108b arranged at both ends of the magnetic sensing part 108a. The thin film coil includes an excitation coil 104 for repeating magnetization saturation of the magnetic sensing unit 108a and a detection coil 112 for detecting a pulse output when the magnetization is reversed. Both the excitation coil 104 and the detection coil 112 are alternately wound around the magnetic sensing part 108 a of the magnetic core material 108.

The parallel fluxgate type magnetic sensor element having such a configuration obtains an output proportional to the magnetic field by the following detection principle.
First, a triangular wave current is applied to an exciting coil wound around a magnetic core material. Due to the triangular wave-like magnetic field generated by the triangular wave current, the magnetic core in the exciting coil repeats magnetization saturation and inversion along the BH curve. This reversal of the magnetization of the magnetic core is detected as a current pulse by the detection coil.
Here, if the frequency of the triangular wave current applied to the excitation coil does not change, the timing of the pulse detected by the detection coil is shifted according to the magnitude of the external magnetic field. An output corresponding to the magnitude of the external magnetic field can be obtained by extracting the time change of the pulse generation by the detection circuit.

Although not shown, an electronic compass is configured by arranging two or three of such magnetic sensor elements so that the directions of the magnetic sensing portions are orthogonal to each other.
When the magnetic sensor element is rotated once in the same plane, the output of the magnetic sensor element shows a sine curve. The outputs of the magnetic sensors arranged in the orthogonal direction have an output relationship with different phases, and the azimuth angle can be calculated from the outputs of the magnetic sensor elements.

JP 2007-279029 A (page 6-8, FIG. 1)

  However, the conventional magnetic sensor element described above has the following problems. In the conventional magnetic sensor element shown in FIG. 5, the excitation coil and the detection coil are alternately wound around the magnetic sensitive part of the magnetic core material. For this reason, the number (number of turns) by which the exciting coil and the detection coil are wound cannot be increased. In particular, when the magnetic sensing portion of the magnetic core material is shortened for miniaturization or the like, the number of turns of the excitation coil and the detection coil is reduced.

  The magnitude of the detection pulse is proportional to the number of turns of the detection coil. For this reason, when the number of turns of the detection coil is reduced, the detection pulse is reduced, and there is a problem that the accuracy of detecting the magnetic field is reduced. The magnetic flux formed on the magnetic core material is proportional to the number of excitation coil turns and the excitation current. For this reason, as the number of turns of the exciting coil decreases, the exciting current has to be increased, and there is a problem that power consumption increases.

  A decrease in the detection accuracy of the magnetic sensor means that the magnetic field cannot be measured stably, and the orientation cannot be obtained correctly when an electronic compass is configured. In addition, an increase in power consumption naturally means a reduction in battery life, both of which are undesirable problems for a magnetic sensor element mounted on a portable information terminal or the like.

  Therefore, in view of the above problems, the present invention provides a magnetic sensor element that stably detects magnetism with high accuracy even when downsized and consumes less power, and an electronic compass equipped with the magnetic sensor. Objective.

  In order to solve the above-described problems, a magnetic sensor element and an electronic azimuth meter according to the present invention have the following configurations.

  The magnetic sensor element of the present invention is a magnetic sensor element comprising a detection unit formed by winding a detection coil around a magnetic core material, and an excitation unit formed by winding an excitation coil around the magnetic core material. The detection unit and the excitation unit are formed in different locations of the magnetic core material, and include a plurality of at least one of the detection unit and the excitation unit. The magnetic core material includes a magnetic coupling unit that couples both ends of the detection unit and the excitation unit to each other. It is characterized by having.

  The magnetic sensor element of the present invention is characterized by having a plurality of excitation portions.

  In addition, the magnetic sensor element of the present invention is characterized in that, when there are a plurality of excitation units, the detection unit is located between the two excitation units.

  The magnetic sensor element of the present invention is characterized by having a plurality of detection units.

Further, the magnetic sensor element of the present invention is characterized in that, in the case where a plurality of detection units are provided, the excitation unit is located between two detection units.

  The magnetic sensor element of the present invention is characterized in that the magnetic core material in the excitation part is divided by a gap having a predetermined width.

  The magnetic sensor element of the present invention is characterized in that the magnetic coupling portion is rounded in the vicinity of the ends of the detection portion and the excitation portion.

  The magnetic sensor element of the present invention is characterized in that the detection coil and the excitation coil are formed of thin film coils.

  The electronic azimuth meter of the present invention is characterized in that any one of the magnetic sensor elements described above is disposed on a nonmagnetic base.

  In the electronic compass of the present invention, three magnetic sensors are arranged on a non-magnetic base, and each magnetic sensor has a direction in which the longitudinal directions of the detection parts are orthogonal to each other, and constitutes a three-axis magnetic sensor. It is characterized by doing.

  In the magnetic sensor element of the present invention, the detection portion around which the detection coil is wound and the excitation portion around which the excitation coil is wound are formed at different locations on the magnetic core material. Thereby, it is possible to increase the number of turns of each of the detection coil and the excitation coil. Therefore, according to the present invention, it is possible to provide a magnetic sensor element that can detect magnetism stably and accurately and consumes less power, and an electronic azimuth meter equipped with the magnetic sensor.

[Description of magnetic sensor element]
The magnetic sensor element of the present invention is basically composed of a magnetic core material made of a soft magnetic material and a thin film coil, and the magnetic core material adopts a configuration having a plurality of excitation units or detection units. is there. The specific configuration will be described in detail in the following embodiments.
<Example 1>

  First, the magnetic sensor element of Example 1 of the present invention will be described. FIG. 1 is a plan view showing the configuration of the magnetic sensor element 1 of the first embodiment. The magnetic sensor 1 according to the first embodiment includes two excitation units and one detection unit as described later.

  The magnetic sensor element 1 has a configuration in which a thin film coil is wound around a magnetic core material 8. As shown in FIG. 1, the magnetic core material 8 includes one detection unit 8a, two excitation units 8b, and a magnetic coupling unit 8c that couples both ends of the detection unit 8a and the excitation unit 8b to each other. It is configured and has an 8-shaped shape as a whole. The magnetic coupling portion 8c is formed in a rounded shape near the detection portion 8a and the excitation portion 8b so that the change in shape is smooth with respect to the detection portion 8a and the excitation portion 8b.

  An excitation coil 5 that is a thin film coil is wound around the two excitation portions 8 b of the magnetic core material 8 to form the excitation portion 5. A detection coil 12, which is a thin film coil, is wound around the detection unit 8 a of the magnetic core material 8 to form the detection unit 13. As shown in FIG. 1, the detection unit 13 is positioned between the two excitation units 5. In addition, an insulating layer (not shown) that electrically insulates the magnetic core material 8 from each coil is formed so as to cover the magnetic core material 8.

Electrode pads for connecting to an external circuit are provided at both ends of each thin film coil. Electrode pads 15 and 15 ′ are provided at both ends of one exciting coil 4, and electrode pads 16 and 16 ′ are provided at both ends of the other exciting coil 4. By connecting the electrode pads 15 ′ and 16 ′, the two exciting coils 4 are connected. Electrode pads 17 and 18 are provided at both ends of the detection coil 12.

With the magnetic sensor element 1 having the above-described configuration, an output corresponding to the magnitude of the external magnetic field can be obtained as follows.
The electrode pads 15 ′ and 16 ′ are connected, and a triangular wave current is applied to the two exciting coils 4 from the electrode pads 15 and 16. Thereby, a magnetic field (magnetic flux) is formed in the exciting part 8 b of the magnetic core material 8 by the two exciting coils 4. The magnetic flux formed in the excitation unit 8b flows to the detection unit 8a through the magnetic coupling unit 8c.

When the current flowing through the two exciting coils 4 is positive (current flows from the electrode pads 15 to 16), the magnetic flux in the direction of the solid line arrow in FIG. 1 flows through the magnetic core material 8. Conversely, when the currents flowing through the two exciting coils 4 are negative (current flows from the electrode pads 16 to 15), the magnetic flux in the direction of the broken arrow in FIG.
The magnetic core material 8 repeats magnetization saturation and reversal along the BH curve by the triangular wave magnetic field generated by the applied triangular wave current, and when the magnetization is reversed, a detection pulse due to the induced electromotive force is generated in the detection coil 12. To do. An output corresponding to the magnitude of the external magnetic field can be obtained by extracting the time change of the detection pulse by the detection circuit.
Here, each magnetic coupling portion 8c has a role of collecting an external magnetic field in order to allow a large amount of magnetic flux to flow into the detection portion 8a.

In the magnetic sensor element 1, the detection unit 13 around which the detection coil 12 is wound and the excitation unit 5 around which the excitation coil 4 is wound are formed at different locations on the magnetic core material 8. Thereby, it is possible to increase the number of turns of each of the detection coil 12 and the excitation coil 4 as compared with the conventional technique in which the detection coil 12 and the excitation coil 4 are alternately wound around the same portion of the magnetic core material 8. Become.
For example, when the detection unit 8a and the excitation unit 8b of the first embodiment shown in FIG. 1 and the conventional magnetic sensing unit 108a shown in FIG. 5 have the same length, the first embodiment is compared with the conventional technology. Thus, the number of turns of the detection coil 12 can be doubled and the number of turns of the exciting coil 4 can be quadrupled.

As described above, the magnitude of the detection pulse detected by the detection coil 12 is proportional to the number of turns of the detection coil 12. For this reason, in the magnetic sensor element 1 of the present invention, the detection pulse is increased by increasing the number of turns of the detection coil 12, and the accuracy of magnetic field detection can be improved.
Further, the magnetic flux formed in the magnetic core material 8 is proportional to the number of turns of the exciting coil 4 and the exciting current. For this reason, in the magnetic sensor element of the present invention, by increasing the number of turns of the exciting coil 4, the exciting current can be reduced and the power consumption can be reduced.

  The magnetic sensor element 1 according to the first embodiment includes two excitation units 5 for one detection unit 13. Thereby, the number of turns of the exciting coil 4 of the exciting part 5 can be increased, and the exciting current can be reduced to reduce the power consumption.

  In the magnetic sensor element 1 of the present invention, both ends of the detection unit 8 a and the excitation unit 8 b of the magnetic core material 8 are coupled by the magnetic coupling unit 8 c of the magnetic core material 8. As a result, a loop of the magnetic core material 8 is formed between the detection unit 13 and the excitation unit 5, and the flow of magnetic flux can be made smooth by suppressing the influence of the demagnetizing field. In the magnetic sensor element 1 of the present invention, the magnetic coupling portion 8 c is formed rounded in the vicinity of each of the detection portion 13 and the excitation portion 5. Thereby, the flow of magnetic flux between the detection unit 13 and the excitation unit 5 and the magnetic coupling unit 8c can be further smoothed.

Furthermore, in the magnetic sensor element 1 according to the first embodiment illustrated in FIG. 1, the detection unit 13 is located between the two excitation units 5. As a result, the magnetic flux formed on the magnetic core material 8 by the two excitation units 5 can be efficiently passed to the detection unit 13.
Moreover, in the magnetic sensor element 1 of Example 1 shown in FIG. 1, the detection part 13 and the excitation part 5 have the substantially same length, and are arrange | positioned side by side. That is, the excitation unit 5 is located in a region formed by the detection unit 13 moving in a direction substantially orthogonal to the longitudinal direction of the detection unit 13. This increases the number of turns of the detection coil 12 and the excitation coil 4 without increasing the size of the detection unit 13 in the longitudinal direction, thereby improving the accuracy of magnetic field detection and reducing power consumption.

  In the magnetic sensor element 1, the detection coil 12 and the excitation coil 4 are formed at different locations on the magnetic core material 8, so that the detection coil 12 and the excitation coil 4 are located at the same location on the magnetic core material 8. Compared with the conventional technique of alternately winding, it is possible to prevent the detection coil 12 and the excitation coil 4 from being short-circuited.

Hereinafter, magnetic sensor elements of Example 2 and Example 3, which are other embodiments of the present invention, will be described with reference to the drawings. In the following description, the same reference numerals are given to the same components already described, and a part of the description is omitted. In the magnetic sensor elements of Example 2 and Example 3, similarly to Example 1, the detection coil 12 and the excitation coil 4 are wound around the magnetic core material 8, and the detection unit 13 and the excitation unit 5 are formed, respectively. It has a configuration.
<Example 2>

FIG. 2 is a plan view illustrating a configuration of the magnetic sensor element 2 according to the second embodiment. The magnetic sensor 2 according to the second embodiment includes two detection units 13 for one excitation unit 5.
The magnetic core material 8 of the magnetic sensor element 2 includes one excitation unit 8b, two detection units 8a, and a magnetic coupling unit 8c that connects both ends of the detection unit 8a and the excitation unit 8b. As shown in FIG.
A detection coil 12 that is a thin film coil is wound around the two detection parts 8a of the magnetic core material 8, and a detection part 13 is formed. An excitation coil 4 that is a thin film coil is wound around the excitation part 8b. Excitation part 5 is formed. The excitation unit 5 is located between the two detection units 13.

  Similar to the first embodiment, a triangular wave current is applied to the exciting coil 4 to form a magnetic flux in the magnetic core material 8 in the direction indicated by the solid and broken arrows in FIG. Due to this magnetic flux, the magnetic core material 8 repeats magnetization saturation and inversion along the BH curve, and when the magnetization is inverted, a detection pulse by the induced electromotive force is generated in the detection coil 12. An output corresponding to the magnitude of the external magnetic field can be obtained by extracting the time change of the detection pulse by the detection circuit.

Also in the magnetic sensor element 2 according to the second embodiment, as in the first embodiment, the detection portion around which the detection coil is wound and the excitation portion around which the excitation coil is wound are formed at different portions of the magnetic core material. Thus, it is possible to increase the number of turns of each of the detection coil and the excitation coil.
For example, when it is assumed that the detection unit and the excitation unit of Example 2 shown in FIG. 2 and the conventional magnetic sensing unit shown in FIG. 5 have the same length, in Example 2, compared to the prior art, It is possible to double the number of turns of the exciting coil and quadruple the number of turns of the detection coil.

Therefore, also in the magnetic sensor element of Example 2, it becomes possible to detect magnetism stably and accurately, and to reduce power consumption.
Moreover, in the magnetic sensor element of Example 2 shown in FIG. 2, the excitation part is located between two detection parts. As a result, the magnetic flux formed on the magnetic core material by the excitation unit can efficiently flow to the two detection units.

  The magnetic sensor element according to the second embodiment includes two detection units 13 for one excitation unit 5. As a result, the number of turns of the detection coil 12 of the detection unit 13 can be increased, the detection pulse of the detection coil 12 can be increased, and the accuracy of magnetic field detection can be further improved.

In the above description, the first embodiment includes two excitation units 5 and one detection unit 13, and the second embodiment includes two detection units 13 and one excitation unit 5. However, the number of the excitation parts 5 and the detection parts 13 of this invention is not limited to these. For example, a plurality of both the excitation unit 5 and the detection unit 13 may be provided in accordance with the magnetic field detection sensitivity and power consumption required for the magnetic sensor element.
<Example 3>

Next, a magnetic sensor element according to Example 3 of the present invention will be described. FIG. 3 is a plan view showing the configuration of the magnetic sensor element 3 according to the third embodiment. As shown in FIG. 3, the magnetic sensor element 3 according to the third embodiment includes a division unit 8 d in which the excitation unit 8 b of the magnetic core material 8 is divided at a predetermined interval in the excitation unit 5. Thereby, the magnetic sensor element 3 of Example 3 has the following effects in addition to the effects of the above-described examples.
By providing the dividing portion 8d, in the magnetic core material 8, the magnetic resistance of the exciting portion 8b is higher than that of the detecting portion 8a. That is, the magnetic flux flows more easily in the detection unit 8a than in the excitation unit 8b. As a result, it is possible to collect a large amount of magnetic field from the outside, which is a detection target, by the detection unit 13, and it is possible to increase the detection sensitivity of the magnetic field.

  In FIG. 3, the example of the magnetic sensor element 3 provided with the two excitation parts 5 and the one detection part 13 was shown. However, the number of the excitation units 5 and the detection units 13 according to the present invention is not limited to this. For example, the magnetic sensor element including one excitation unit 5 and two detection units 13 illustrated in FIG. It can also be applied to. Regardless of the number of the excitation units 5 and the detection units 13, by providing the division unit 8 d in the excitation unit 8 b of the magnetic core material 8, more magnetic fields from the outside are collected by the detection unit 13, thereby detecting the magnetic field. Sensitivity can be increased.

[Description of electronic compass]
Next, the electronic azimuth meter of the present invention will be described with reference to the drawings. FIG. 4 is a perspective view showing the configuration of an electronic azimuth meter 19 that is mounted and arranged on the nonmagnetic base 20 using three magnetic sensor elements of the present invention described above.

As shown in FIG. 4, the electronic compass 19 has an X-axis magnetic sensor element 22 and a Y-axis magnetic sensor, which are three magnetic sensor elements having the same configuration as the magnetic sensor element of the present invention, on a nonmagnetic base 20. The sensor element 24, the Z-axis magnetic sensor element 26, and a magnetic sensor IC (not shown) for driving these magnetic sensor elements are mounted and arranged.
The X-axis magnetic sensor element 22, the Y-axis magnetic sensor element 24, and the Z-axis magnetic sensor element 26 are arranged so that the longitudinal directions of the detection units are orthogonal to each other along the X-axis, Y-axis, and Z-axis, A 3-axis magnetic sensor is configured.
The azimuth angle can be calculated by the magnetic sensor IC based on the detection signal output from the detection coil when an excitation current is passed through the excitation coils of the magnetic sensor elements 22, 24, and 26.

  Then, a sealing resin 28 is applied to protect each magnetic sensor element 22, 24, 26, and further, a magnetic sensor IC is driven on the nonmagnetic base 20 on which these magnetic sensor elements are mounted. A package of the electronic azimuth meter 19 is configured by providing a power supply terminal, an output terminal for outputting azimuth angle data (signal) calculated based on the detection signal of each magnetic sensor element, and the like.

As described above, by mounting the three magnetic sensor elements according to the present invention to constitute the electronic azimuth meter of the three-axis magnetic sensor, the electronic azimuth meter of the three-axis magnetic sensor can be reduced in size and reduced in height. It can be mounted on a portable information terminal.
Note that two magnetic sensor elements according to the present invention can be arranged on a nonmagnetic base in a direction orthogonal to each other to constitute an electronic azimuth meter using a two-axis magnetic sensor. Alternatively, the magnetic sensor element according to the present invention can be mounted on a non-magnetic base with at least four to constitute a more accurate electronic azimuth meter.

It is a top view which shows the structure of the magnetic sensor element of Example 1 of this invention. It is a top view which shows the structure of the magnetic sensor element of Example 2 of this invention. It is a top view which shows the structure of the magnetic sensor element of Example 3 of this invention. It is explanatory drawing which shows the structure of the electronic azimuth meter of this invention. It is a top view which shows the structure of the conventional magnetic sensor element.

Explanation of symbols

1-3 Magnetic sensor element 4 Excitation coil 5 Excitation part 8 Magnetic core material 8a Detection part 8b Excitation part 8c Magnetic coupling part 8d Split part 12 Detection coil 13 Detection part 15-18 Electrode pad 19 Electronic compass meter 20 Nonmagnetic base 22 X-axis magnetic sensor 24 Y-axis magnetic sensor 26 Z-axis magnetic sensor 28 Sealing resin

Claims (10)

In a magnetic sensor element comprising: a detection unit formed by winding a detection coil around a magnetic core material; and an excitation unit formed by winding an excitation coil around the magnetic core material,
The detection unit and the excitation unit are formed at different locations of the magnetic core material,
A plurality of at least one of the detection unit and the excitation unit,
The magnetic core material includes a magnetic coupling unit that couples both ends of the detection unit and the excitation unit to each other. The magnetic sensor element according to claim 1, comprising a plurality of the excitation units. The magnetic sensor element according to claim 2, wherein the detection unit is located between the two excitation units. The magnetic sensor element according to claim 1, comprising a plurality of the detection units. The magnetic sensor element according to claim 4, wherein the excitation unit is located between the two detection units. The magnetic sensor element according to any one of claims 1 to 5, wherein the magnetic core material in the excitation part is divided by a gap having a predetermined width. The magnetic sensor element according to any one of claims 1 to 6, wherein the magnetic coupling unit is formed rounded in the vicinity of the end portions of the detection unit and the excitation unit. The magnetic sensor element according to any one of claims 1 to 7, wherein the detection coil and the excitation coil are formed of a thin film coil. An electronic azimuth meter comprising two or more magnetic sensor elements according to claim 1 arranged on a nonmagnetic base. Three magnetic sensors are disposed on the non-magnetic base,
The electronic azimuth meter according to claim 9, wherein each of the magnetic sensors has a direction in which longitudinal directions of the detection units are orthogonal to each other, and constitutes a three-axis magnetic sensor.

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